Persecution has been widespread across India and China even during the pandemic, but things are only likely to get worse in 2021, Release International has warned.
The charity, which supports persecuted Christians worldwide, says that China has "bought the silence of the international community" through trade relations.
This year has continued to see unregistered churches in the country raided or forced to close.
There is increasing surveillance as authorities in some areas have forced registered churches to install CCTV cameras.
Christians also report some churches having to put up posters proclaiming communist beliefs.
"The government of President Xi Jinping is increasing its 'clean up' of anything that does not advance the communist agenda," Release partners said.
"They appear to believe that they can achieve this by systematic opposition."
The Chinese authorities "have bought freedom from censure due to trade with China. Many countries now regard this trade as essential to their own economies," they added.
The report warns that China has exploited the pandemic to increase its grip of churches, particularly unregistered ones.
Release partner Bob Fu, the leader of ChinaAid who has faced bomb threats this year for his religious liberty work, says the Chinese government has accelerated the forced removal of crosses from churches during the pandemic.
"The Chinese Government is trying every way to take advantage of the virus by increasing the crackdown against Christian churches," he said.
In India, growing Hindu nationalism is behind a rise in the violent persecution of Christians since the BJP (Bharatiya Janata Party) came to power in 2014.
Attacks on Christians and churches have only continued following the re-election of BJP Prime Minister Narendra Modi in a landslide victory in May 2019.
The attacks have not stopped despite the pandemic, with the Alliance Defending Freedom recording 225 incidents of religiously motivated violence against Christians in 2020, up from 218 in 2019.
These include a mob attack by up to 3,000 people against Christians in three villages in Chhattisgarh state in September.
Other countries mentioned in the report include Malaysia, where abducted pastor Raymond Koh remains missing.
Release partners warn that the newly formed government is using the Covid outbreak for their own purposes.
"They have closed churches all over the country, where persecution is definitely increasing," they said.
In Nigeria, Christians continue to be attacked by terrorist group Boko Haram and heavily armed Fulani militants.
Release partners there say that the attacks are increasingly taking on the characteristic of a jihad.
"We have seen well-planned, well-orchestrated, systematic attacks on Christian communities that have nothing to do with a fight for grazing lands," said Release partner Rev Hassan John.
"These attacks are driven by an Islamist ideology, aimed at destroying 'the infidels' and, in many places, displacing them from their communities, while the government, by design or omission turns a blind eye to the carnage."
While some have been killed in raids on largely Christian communities, others have been kidnapped for ransom.
Mark Lipdo, another Release partner in Nigeria, adds: "The failure of governance has led to increased criminality with impunity."
Despite the huge challenges, some good news stories have also emerged this year.
Release's partner in North Korea, one of the toughest countries towards Christianity, says that believers there see the pandemic as an act of God that has opened up new opportunities for them.
This includes a doubling of Bible distributions this year despite the Covid restrictions.
"This has been the most creative year we have witnessed in the underground church to date," the partner said.
And in Iran, Christians have been able to avoid government surveillance by meeting online.
"Persecution is on the increase in Iran because the authorities are aware of the growth in the number of converts and house churches. They are determined at all costs to stem this," say Release partners.
"There is no doubt that the government is concerned that disillusioned Muslims are becoming Christians."
Commenting on the findings of the report, Release CEO Paul Robinson said: "Our partners tell us that attacks are on the rise under Communism in China, Islam in Iran and Malaysia, and under militant Hinduism in India.
"Yet despite persecution and pandemic, we see clear evidence of the boldness, courage and trust in God of Christians under pressure around the world."
